Modern cellular wireless communications systems may be designed to offer mobile wireless communications services such as voice and data to subscribers. In a typical communication service, the wireless transmit/receive unit (WTRU) may communicate to the radio access network (or “network”) requesting service, which service may then be set-up for the WTRU. The WTRU may use the radio resources allocated by the network to perform the voice call or data transfer. Most services may involve a WTRU and another entity which may be located anywhere where connectivity is available. Voice calls may imply two entities in a different part of the same city, while data services may imply a server located in a different country, for example. Since most calls or data services involve entities in separate geographical locations, modern wireless communications systems may not be optimized for the situation where the communicating parties are separated by a (relatively) short distance.
The recent rise in popularity of smart phones is changing the way people use their wireless devices and how services are offered. For example, location based services are becoming more and more the standard. Likewise, social media applications employing location information are emerging and are expected to become very important in the near future. It is expected that applications and services involving two or more nearby devices may cause large amounts of data traffic in networks. One approach to mitigate the increase in network traffic due to these “Proximity Services” may be to limit the traffic to the cell by either allowing direct WTRU-to-WTRU or device-to-device communications (D2D) or to have an evolved Node B (eNB) relay the information. This last option may reduce the data traffic on the network as the data packets no longer have to be carried to the SGSN and back to the originating eNB, thereby offloading the network.